The present invention relates to pigmented paint formulations containing a phosphorus acid functionalized latex binder and a polymeric dispersant for pigment that contains sulfonic acid groups or salts thereof.
The efficacy of the TiO2 as a hiding pigment is reduced when TiO2 particles are allowed to come too close together upon film formation and drying. It is known that the spacing of TiO2 and its concomitant hiding efficiency can be improved with the aid of emulsion polymer particles adsorbed to the TiO2 particle surface. (See US 2003/0018103). One of the potential problems observed with current adsorbing latex technology is slow adsorption kinetics between TiO2 pigment and latex leading to viscosity instability of a formulated paint upon aging. This behavior is especially prominent when using pre-dispersed slurries of TiO2. Such paints can demonstrate incomplete latex adsorption upon formulation, which results in continued latex adsorption in the paint can with accompanying viscosity rise. This viscosity instability alters the targeted rheological properties set by the formulator. It would therefore be desirable to discover a way to increase the initial latex adsorption for slow forming pre-composite technology to alleviate the viscosity instability with aging associated with continued latex adsorption.